Prior art design of grinding mill sand wheel seals, which include Sag, Ag, Ball and Rod mills, see the “sand wheel” as a fabricated bucket design which is mounted or combined with the feed trunion insert. This design only allows the seal to be externally mounted or outside of the actual feed end of the mill.
This design has many issues that are not optimum. First the slurry is allowed to exit the mill before it can be collected then dumped back into the mill. This allows for spillage, which in turn enters the actual trunnion of the mill, creating several problems. The first and most severe problem is the contamination of lubrication systems, however other problems also occur, such as damaged trunnion seals and considerable mess in the surrounding area.
As such, sand wheel seals are mounted externally. They considerably reduce the trunnion internal diameter, thus dictating the size of internal wear parts, and the casting that can be used in the mills. Furthermore this externally restricts the size and/or safe working load of the lining machine which is used to maintain the internals of the mill. In certain instances when a mill is overloaded, large material becomes jammed in the sand wheel between the feed chutes thus destroying the components, which results in necessary repairs or replacement. A further disadvantage of the prior art sand wheel seals, is that they cannot be replaced during a mill reline, and therefore additional downtime is required for their replacement.
It is an object of the present invention to provide a sand wheel seal for a grinding mill that will overcome or substantially ameliorate one or more of the deficiencies of the prior art, or provide a useful alternative.